The Imagin are beings from a possible future who have lost their physical forms due to an event that erases their timeline, becoming dependent on existing through the memories of humans, though this event and timeline are not well explained. Led by Kai, they arrive to the year 2007 to find weak-hearted humans and through them go back in time to find the key figure to the Junction Point(分岐点の鍵,Bunkiten no Kagi?), and destroy him so their future can become a reality again. Imagin possess humans upon forging a contract, fashioning a physical form by searching through the host's memory for figures found in folklore and myths. In some cases of Imagin possession, a person's eyes change color to that of the Imagin, the hair altered into style with a streak of it also changed to the color of the Imagin. In some cases, even the host's attire changes to reflect the Imagin's personality. There are also rare Imagin showing the ability to split into two or more entities that can survive independent of each other. Normally, when this happens, there is a clear difference between them, ether physical or they'll have completely different personalities. Unlike most Kamen Rider villains, who normally have greedy or selfish motives for their actions, the Imagin attack the past due to self preservation, wanting to keep their race alive.

The hosts, recognized by the sands of time spilling from their bodies, are offered a single wish by the Imagin. In exchange, the Imagin is able to dive into the most treasured moment of the person's past. As displayed, however, the host must remember making the contract for the Imagin to successfully travel to the past. Additionally, due to the greatly delicate nature of the contract, if the contract holder forgets or dies before the contract is completed, the Imagin bound to him or her would fade out of existence. Opening the human like a door, a portal is revealed that leads to the appropriate time, severing their ties to the human in the process. From there, the Imagin takes over a host's body or simply manifests itself in its physical form and begins causing massive chaos. In turn, due to the laws of time, everything and everyone destroyed in the past no longer exists in the present and the person in the present time dissolves to sand and possibly becomes an Imagin themself. However, as Ryotaro learned in time, the restoration of these things rely on just being remembered. Also, if an alteration to the past prevents the contract from ever being made in the first place, the damage will be negated completely due to it never having happened, as was the case with the Ivy Imagin. However, it appears that should the Imagin have been destroyed in the past, its destruction is not undone.

A "Singularity Point" (特異点,Tokuiten?, gravitational singularity) in Kamen Rider Den-O is a human who has the ability to exist independent of time itself, and be unaffected by changes in their own past. This ability also allows them to suppress an Imagin's will when it takes over their body and is not tempted by the free wish an Imagin can grant. Because of this, the Imagin contracted to Singularity Points are usually unable to take a physical form in the present time, and directly possess their Singularity Point, instead. They usually reside within time itself and when they are not possessing their Singularity Point, they stay on some sort of Train of Time, such as the DenLiner or the ZeroLiner. The Singularity Points also have the ability to become Kamen Riders, and the Imagin that possess them lend their abilities in combat when called upon. In other instances, the Imagin use their Singularity Point's body as they wish when the Singularity Point loses consciousness. As long as the Singularity Point is conscious, he can expel the Imagin from his body and send it back to the Train of Time that he uses as a Kamen Rider.

The Rider Pass that Ryotaro Nogami uses to become Kamen Rider Den-O can summon at least four Imagin. Each of these Imagin gives Den-O their power when they are called upon with each form suiting to their fighting style. These Imagin are collectively known as the Tarōs (タロウズ,Tarōzu?) due to their namesakes. When not possessing Ryotaro, the Tarōs spend their time in the DenLiner's dining car. However, they are also able to enter physical time and space by possessing vacant forms, such as full-body costumes, although this leaves them physically unstable. The Imagin have also proven capable of possessing Ryotaro all at once after the creation of Climax Form, but outside of their transformed state, this 4-way possession is dangerously unstable and physically stressful for Ryotaro. Due to their nature as Imagin, they can sense evil Imagin near Ryotaro's vicinity and alert him likewise. In addition to powering up Den-O, the four are each armed with a weapon and each are able to perform their form of Den-O's finishing attack in their normal state.

When the Junction Point starts to form, the Tarōs start to lose sync with Ryotaro and are unable to possess him when he travels to the past. To continue to assist him, they create the DenKamen Sword, which allows him to channel their power without direct possession. Though Ryotaro is curious of these recent events, the four are reluctant to explain that it meant the future they came from is being erased, causing their kind to cease to exist as the result of their battle with the evil Imagin. In spite of it, however, the Tarōs intend to keep fighting to the end, gaining physical form within normal space-time as a result of each Imagin granting Ryotaro's wish that they fight together until the end. When the time does come and they fade away, it is revealed that the memories they made with Ryotaro have created a time lag, allowing them to maintain their existence as they take leave on the DenLiner.

Momotaros (モモタロス,Momotarosu?) is the first Imagin that gives Ryotaro his power, which allows for the Sword Form transformation. He can also sense when an Imagin is rampaging in the city, subsequently alerting Ryotaro immediately. His natural weapon as an Imagin is a sword named the Momotarosword (モモタロスォード,Momotaroswōdo?). Momotaros blames Ryotaro for his Oni-like form, though it matches his personality, best described as hot blooded, arrogant, and comedic, serving as a foil to Ryotaro's own shy and cowardly personality. In fact, Momotaros is more interested in fighting than carrying out the Imagin's goal. Unfortunately, he is constantly beaten by Hana when he gets Ryotaro into trouble. When he possesses Ryotaro, declaring the words "Here I come!" (俺、参上！,Ore, sanjō!?),[1] Momotaros's own personality takes over, giving Ryotaro power, confidence, and a bit of his eagerness for a good fight. His eagerness is shown in battle, where he always declares the words, "I am, from start (to finish), at the climax!" (俺は最初から（最後まで）クライマックスだぜ！,Ore wa saisho kara (saigo made) kuraimakkusu da ze!?). Momotaros is also somewhat selfish, initially fighting alongside Ryotaro in order to ensure his own survival. Though he unknowingly places Ryotaro in unneeded danger to suit his fancy, Momotaros eventually learns to respect him and his desire to protect others. Though he demands respect, Momotaros is usually put in his place by Hana and her powerful punches. He also does not know how to swim, has a narcotic reaction to red peppers, and seems to be afraid of dogs. While he acts hostile and demeaning to the other Tarōs, he does care about them, proven by hiding his anguish while they are slowly disappearing due to the events of the Climax Scene. Momotaros is the base for Den-O's Climax Form, as he has control of the head and torso and can control the other sections that the other Tarōs usually have primary control of if need be. During the events of OOO, Den-O, All Riders: Let's Go Kamen Riders, Momotaros assumed both the forms of the Momotaken for New Den-O to use and then the Imagin Medal for Kamen Rider OOO to use to assume Tamashii Combo.

When insulting another Imagin, he usually calls them a "X-Jerk" (Ｘ野郎,X-yarō?) depending on the animal they are modeled after, or a shortened version. The other exceptions are Ryutaros, referred as "Brat" (小僧、ガキ,Kozō, Gaki?) or "Snot-nosed Brat" (ハナタレ小僧,Hanatare Kozō?), Deneb as "Tubby" (オデブ,Odebu?), and Teddy as "Tendon" (天丼?). Momotaros also refers to Hana as literally "Nosy Woman" (ハナクソ女,Hanakuso Onna?). He also puts emphasis on his final blow attacks, saying "My Finishing Attack, Part X" (俺の必殺技パートＸ,Ore no hissatsu waza pāto X?) while possessing Ryotaro in Den-O Sword Form, with a Part 1, 2, 2’ (Two-Dash), 3, and 5 (Ryotaro tells Momotaros that he skipped 4, but he considers not using 4 "cool", even counting from 1-10 while skipping 4). In his battle against Kamen Rider Gaoh, Den-O Sword Form swiped the Rider Pass over the Den-O Belt twice, initiating a doubled Full Charge for "My Finishing Attack, Special Edition" (俺の必殺技・特別編,Ore no hissatsu waza tokubetsu hen?). In his battle against the Alligator Imagin in Kamen Rider Decade, while empowered by Decade's Final AttackRide Card, Momotaros uses Kuuga Gouram and a DenGasher for his "My Finishing Attack, Decade Version" (俺の必殺技・ディケイドバージョン,Dikeido Bājon?). When performing his version of the attack in his physical form, he calls it "My Finishing Attack, Momotaros Version". His physical form is based on an oni and a peach and his DenLiner train features a dog, monkey, and bird, all of which are companions of Momotarō(桃太郎?) the Peach Boy. Ironically, the legend has Momotaros's namesake defeating evil oni, while Momotaros is based on an oni.

Urataros (ウラタロス,Uratarosu?) is the second Imagin that gives Ryotaro his power, allowing transformation into Den-O Rod Form. The form given to him by Ryotaro is turtle-like in appearance, with his weapon being the Uratarod (ウラタロッド,Urataroddo?), a rod with hexagonal blades at each end. Furthermore, Urataros was well-aware of Ryotaro being a Singularity Point, making his contract to him on purpose—though he says it is to evade the loneliness of being outside time, Hana later debunks this entirely. When he possesses Ryotaro, he usually states the words, "Hey, will you let me reel you in?" (お前、僕に釣られてみる？,Omae, boku ni tsuraretemiru??).[1]

He is also aware of the evil Imagin planning to destroy time, but simply does not want to commit it as in spite of his cool exterior, there's indication that he's somewhat of a coward and lies just for self preservation. Urataros is a casanova with a very convincing personality, owning the ability to convince almost anyone by speaking to them, with Ryotaro the only one who trusts him and lets him stay as he sees he has a good heart. Urataros, however, later says that he lies simply for the sake of lying ("One lie is more interesting than a thousand truths"), and seems quite irritated that Ryotaro is "trivializing his lies."

While Momotaros gets Ryotaro in trouble through reckless methods, Urataros puts Ryotaro in conflicting situations when he goes around wooing multiple women. Despite these negative traits, along with his occasional fights with Momotaros, Urataros does show genuine concern for Ryotaro's well being. Being the best speaker of the Taros, possessing Ryotaro simply to get information out of someone, or to talk his way out of something. He is also useful in situations that require patience, something Momotaros severely lacks.

He usually refers to Momotaros as "Sempai" (先輩,Senpai?) and Kintaros as either "Bear" (クマ,Kuma?) or "Kin-chan" (キンちゃん,Kin-chan?) respectively. Urataros' physical form is based on that of a turtle and fishing rods are a common motif, both of which are aspects of the myth of Urashima Tarō(浦島太郎?), a fisherman who caught a turtle that led him to the castle of Ryūjin.

Urataros is voiced by Kōji Yusa(遊佐 浩二,Yusa Kōji?), who was also known as the voice of Shadow the Hedgehog from Sonic the Hedgehog franchise.

Kintaros (キンタロス,Kintarosu?) is the third Imagin that gives Ryotaro his power, which allows for the Ax Form transformation. He is vaguely modeled after a bear and has a Sumo wrestler-like personality. He also has a habit of deep sleeping (akin to hibernation) until the mere mentioning of any word that sounds remotely similar to the Japanese word for "to cry" (泣く,naku?) often provokes Kintaros out of his slumber to possess Ryotaro in an instant.

He speaks in the dialect of Kansai-ben, saying, "My strength has made you cry. Wipe your tears with this!" (俺の強さに、お前が泣いた。涙はこれで拭いとけ,Ore no tsuyosa ni, omae ga naita. Namida wa kore de fuitoke?),[1] whenever he possesses Ryotaro, taking out a handkerchief for whoever wants to wipe their tears off with. His natural weapon as an Imagin is a giant battleaxe named the Kintaros Axe (キンタロスアックス,Kintarosu Akkusu?). He has a habit of popping his neck every time he begins and ends a battle, as well having "You cried" (泣けるで,Nakeru de?) as a battlecry.

Kintaros is a strong Imagin who constantly seeks opponents stronger than himself. Unfortunately, he is sometimes unable to control his own strength resulting in accidentally destroying things, which he attempts to fix afterward. He is also very selfless and had no intent to follow Kai's orders to alter time to begin with. At first, he is dependent on a retired karateka named Masaru Honjō, who gave him his "bearish" look, as he attempted to master karate so Masaru could achieve the "ultimate karate". Kintaros wants to teach Masaru the ultimate karate, in order to let him settle things with Kikuchi instead of disturbing the timestream.

Seeing the good side of Kintaros when he protects Masaru from the Rhino Imagin and being mortally wounded in doing so, Ryotaro allows Kintaros to enter a contract with him, saving the Imagin's life. Unlike the others, who had (at least partly) selfish intentions for assisting Ryotaro, Kintaros's motives for helping him are noble from the start, having a desire to repay Ryotaro for saving his life, stating so on several occasions.

He usually refers to Momotaros as "Peach" (桃の字,Momonoji?), mispronouncing his name as "Momonga" (モモンガ,Momonga?, Japanese Dwarf Flying Squirrel) and "Momohiki" (モモヒキ,Momohiki?, Long Underpants) and refers to Urataros as "Turtle" (亀の字,Kamenoji?). Kintaros' physical form, based on that of a strong golden bear, are aspects of the traditional myth of Kintarō(金太郎?) the Golden Boy, said to be strong enough to wrestle bears and demons.

Ryutaros (リュウタロス,Ryūtarosu?) is the fourth Imagin that gives Ryotaro his power, which allows for the transformation into Den-O Gun Form. His natural weapon as an Imagin is a shotgun named the Ryuvolver (リュウボルバー,Ryūborubā?). Though he is the last Imagin to appear, Ryutaros initially possessed Ryotaro the moment that Urataros did, and simply hid himself from the others. Ryutaros reveals himself in his form when he is attracted by Naomi's coffee inside the DenLiner. Ryutaros is most childish in personality with a love for drawing and animals. Ryutaros also appears to enjoy break dancing, to the point to that it is incorporated into his flashy fighting style. His personality is one of a fun-loving dancer/disc jockey but is reckless. This recklessness also causes the most collateral damage, as he fires his gun aimlessly.

When he possesses Ryotaro, he first asks "Mind if I...?" (…いい？,...Ii??, usually "Mind if I defeat you?" or "Mind if I end this?") followed by "I can't hear your answer" (答えは聞いてない,Kotae wa kiitenai?).[1] He has the ability to control people simply by snapping his fingers. This tactic works with summoning the Machine DenBird as well. Originally, Ryutaros possesses Ryotaro after being promised the title of become the DenLiner's conductor by Kai, who also gives the Imagin a ticket, on the condition that he destroys Ryotaro.

However, because he does not wish for Airi to cry, Ryutaros decides not to destroy Ryotaro. The only individual he will listen to is Airi, whom he affectionately calls "sis" (お姉ちゃん,onee-chan?, Ryotaro only calls her the more formal "sister" (姉さん,nee-san?)). Because he knows that Airi has loved Yuto Sakurai, and from faulty advice on love from Kintaros, he becomes jealous of Yuto and wishes to show that he is stronger than him. But when Kai takes matters in his own hands in killing him, combined with realizing how he and Airi can not to be together, Ryutaros matures a bit to cope with fading away while eventually mustering courage to fight in the final battle against Kai.

He usually refers to Urataros, Kintaros, Sieg, Teddy respectively as "Turtle-chan" (カメちゃん,Kame-chan?), "Bear-chan" (クマちゃん,Kuma-chan?), "Bird-san" (トリさん,Tori-san?), and "Blue Bear-chan" (青クマちゃん,Aoikuma-chan?). However, he excludes Momotaros as he is not based on an animal and Momotaros does not understand him like the others do. He is referred to by the others as "Ryuta" (リュウタ,Ryūta?). After this initial arrival on the DenLiner, he is rarely seen without a pair of headphones over his head.

One of the Tarōs, Ryutaros's basis is unclear as early promotional material stated his form to be based on the legend of Tatsu no Kotarō (Taro the Dragon Boy) while TV Asahi's website for Den-O states that his form is based on Ryotaro's mental image of dragons. Two of the Imagin Anime shorts bring up the topic of Ryutaros's possible namesake.

Ryutaros is voiced by Kenichi Suzumura(鈴村 健一,Suzumura Ken'ichi?), who was also known as the voice of Kouichi Kimura from Digimon Frontier.

Deneb (デネブ,Denebu?) is an Imagin fully contracted to Yuto Sakurai, gaining a physical form within normal spacetime due to Sakurai's wish for the Imagin to aid his past self as part of their contract. Rather than possessing him to travel into the past, Deneb willingly betrays Kai and possesses Sakurai in the middle of a fight after witnessing his desire to protect time as Zeronos. Deneb serves as Yuto's butler and fights alongside him while he is in Altair Form, able to fires bullets (or smoke pellets) out of his fingertips. He also provides Zeronos the ability to transform into Vega form. He carries around a basket that contains hand-made candies that have wrappers that bear his face called "Deneb Candy" (デネブキャンディー,Denebu Kyandī?). His personality is the polar opposite of Yuto's, with Deneb's noble demeanor usually resulting in embarrassing consequences done to Yuto, who comically beats him up for it. Although Yuto treats him with occasional disrespect; Deneb chooses to stand by his side out of friendship and loyalty, knowing Yuto to be a kind person. He also acts as a parental figure to Yuto, doing his best to make sure he lives healthy, including a need to serve shiitake to him, despite Yuto's hatred towards it (and usually resulting beating up). Due to the fact he has a physical form in normal spacetime, Deneb often appears in (poorly constructed) disguises in order to avoid standing out.

Due to Deneb's limited interaction with the Tarōs, he does not have names for them. However, he has on one occasion called Kintaros "Kumagoro" (くまごろう,Kumagorō?) and Urataros as "Kametaros" (カメタロス,Kametarosu?). Deneb is also the only Imagin other than Ryutaros to call Momotaros by his actual name as opposed to a nickname. Deneb is also the only main Imagin who does not have his own catchphrase, although merchandise from Toei and Bandai often feature Deneb saying "Please take care of Yuto" (侑斗をよろしく,Yūto o yoroshiku?).[1] Upon transforming into Vega Form, Deneb often starts out with "Let me say this to start..." (最初に言っておく…,Saisho ni itte oku...?), followed by something honest. The first instance was "This face on my chest is just for show!" (胸の顔は飾りだぁっ！,Mune no kao wa kazari daa'!?). Deneb's physical form is based on the historical story of Benkei and the fictional Karasu-Tengu. He is also named after the star Deneb in the constellationCygnus the Swan which is important in the legend of the Tanabata along with "Altair" and "Vega", the names of the two forms that Zeronos can initially access.

Sieg (ジーク,Jīku?) is an Imagin who enables Den-O's transformation into Wing Form. He arrives in the current timeline six months prior to Ryotaro becoming Den-O, originally intending to forge a contract with a young wealthy pregnant woman named Shiori Takayama, but possesses her unborn son in the process. After the child is born and subsequently kidnapped, Sieg comes into being and seeks to reunite his "brother" with their "mother", crossing paths with Ryutaros and gaining access to the DenLiner. Due to his "privileged" upbringing and his already princely mannerisms, Sieg becomes easily infuriated when treated with disrespect. Because he is "born" in 2007, he also possesses extraordinary unique abilities. Aside from shrinking the Tarōs to 4 inches tall with the phrase "Kneel down to me!" (頭が高い!,Zu ga takai!?),[1] he also cannot be forcibly removed from Ryotaro's body as he does not need a contract to possess humans. When possessing Ryotaro, Sieg says "Descending, yet above it all..." (降臨、満を持して…,Kōrin, man o jishite...?). He almost vanishes due to his contract holder being a newborn child and unable to form proper memories, but Ryotaro is able to discover that Sieg actually made a contract with the mother to ensure her then unborn son's safety, saving Sieg's life in the process. As his contract has been fulfilled, the DenLiner takes Sieg to the date of his Shiori's greatest memory and lives in the past freely. After his appearances in the television series, he appears in the films Kamen Rider Den-O: I'm Born! and Saraba Kamen Rider Den-O: Final Countdown allowing for the transformation into Wing Form, and again in Cho Kamen Rider Den-O & Decade Neo Generations: The Onigashima Warship, pestering Tsukasa's group until brought to the climatic battle to join the Tarōs in forming Super Climax Form. He also appeared in Cho-Den-O Trilogy Episode Blue: The Dispatched Imagin is Newtral.

During his first time on the DenLiner, he demanded that the others call him "Prince" (プリンス,Purinsu?) and asked for Hana to be his "Princess" (姫,Hime?), and was punched for each time he called her that. After his return, Sieg refers to the Tarōs as his "family" instead of his "friend" phrasing. In the Imagin Anime OVA, Sieg had an additional power "Super-Ultra Kneel down to me!" (スーパーウルトラ頭が高い!,Sūpā-Urutora Zu ga takai!?) that allows him to shrink everything in sight, even an entire planet. His name is given as "Zieg" in the series' photobook DETAIL OF HEROES: Masked Rider Den-O Exclusive Photograph Collection: IMAGINE(DETAIL OF HEROES 仮面ライダー電王特写写真集 IMAGINE,DETAIL OF HEROES Kamen Raidā Den'ō Tokusha Shashinshū: Imajin?), however, other materials give his name as "Sieg," such as the earlier photobook Masked Rider Den-O Photobook: IMAGIN(仮面ライダー電王フォトブック IMAGIN,Kamen Raidā Den'ō Fotobukku Imajin?). Sieg's physical form and name are based on swan and Prince Siegfried (ジークフリート王子,Jīkufurīto Ōji?) from the story Swan Lake(白鳥の湖,Hakuchō no Mizuumi?).

Teddy (テディ,Tedi?) is Kotaro Nogami's Imagin partner from the future, able to assume the form of the Macheteddy (マチェーテディ,Machētedi?, from "machete") sword New Den-O uses as Strike Form. He is a polite and reserved character in general, humbling himself to his friends. Unlike the other Imagin, his form is based on the stories that Kotaro was told by the Owner of his grandfather Ryotaro Nogami's exploits with the Tarōs as Kamen Rider Den-O. As such, the name he is initially given is "Neotaros" (ネオタロス,Neotarosu?), as evident by the designs resembling the letters NEO on his body, until Kotaro renames him after experiencing his grandfather's true meek life. Like Sieg, Teddy is a special case as he can sense whenever his contract holder is in any immediate danger and neutralize it. It has been described that Teddy is the Sancho Panza to Kotaro's Don Quixote.[2]

Teddy first appears with Kotaro during the events of Saraba Kamen Rider Den-O: Final Countdown, both serving to replace Ryotaro and the Tarōs as protectors of spacetime. When Shiro travels back in time to May 23, 1729, and the New DenLiner gang follows, Teddy is the one who learns of Shiro's plans to attack the small village nearby and is seriously wounded by Shiro's forces. He recovers in time to help in the final battle against Kamen Rider Yuuki. But during the events of Episode Blue: The Dispatched Imagin is Newtral, Teddy is forced to set up a new contract with the Owner as his original contract had expired in the events of Final Countdown and is renamed Aleksandrovic (アレクサンドロヴィチ,Arekusandorovichi?). Though he nearly destroys himself in the process by derailing from his contract to help Kotaro, Teddy becomes his partner again.

An evil version of Momotaros, Negataros (ネガタロス,Negatarosu?) and a select few Imagin are stray Imagin who evaded the fate of the other evil Imagin when Kai ceased to exist in the final episode. From there, he comes to possess a stolen Rider Pass, allowing him to assume an evil version of Den-O Sword Form called Nega Den-O(ネガ電王,Nega Den'ō?). Recruiting members of the Fangire Race and mobsters to his aid, Negataros intends to restore the future where the Imagin came from. But Negataros has to deal with both the DenLiner Police (デンライナー署,Denrainā Sho?) led by Ryotaro Nogami, an inside man in the form of Yuto Sakurai, further worsened by the brief meddling of Wataru Kurenai.

In the end, Negataros' plan is foiled and his armor is destroyed by the Double Boistous Kick & Darkness Moon Break of Kiva & Den-O Climax Form before he finally meets his end in battle while using the Nega DenLiner against the DenLiner, the ZeroLiner and Castle Doran.

Negataros is also featured prominently in the S.I.C. Hero Saga (S.I.C.ヒーローサーガ,Esu Ai Shī Hīrō Sāga?) in Hyper Hobby Magazine. The story is a retelling of the events of Climax Deka featuring Negataros travelling to April 3, 1971, to team up with the Shocker organization and combating Den-O and the Tarōs along the way.

As Negataros is an evil version of Momotaros, his physical form is also based on the myth of Momotarō(桃太郎?).

Eve (イブ,Ibu?) is an artificial Doberman Pinscher Imagin created by the Time Police and partnered to Reiji Kurosaki. Being an artificial Imagin, Eve has infinite knowledge and is able to counter any attack which he uses greatly even when he is not the one fighting. Like Kurosaki, Eve has little emotion, thinking only about duty and performing judgement. But when Kurosaki starts showing emotion, Eve deems humanity too illogical to exist and becomes G Den-O himself to execute everyone. He was then destroyed after Diend in Complete Form used the Gekijouban card along with Kamen Rider Den-O Climax Form along with the G Den-O system.

The Bat Imagin possesses ability to create wings to fly and use sonic wave as weapon, the Bat Imagin fulfills his contract with the Tetsuo for return of his jinglebell keyholder. Attacking everyone with a jinglebell keyholder. The Bat Imagin battled Den-O Sword Form, but the fight ended in being defeated, however. The Imagin managed to survives from Den-O's final attack. When he travels to the past, the Bat Imagin possesses Tetsuo's body and begins causing havoc until Den-O appears and forces him to abandon Tetsuo. And he is destroyed by Den-O, he then becomes Gigandeath Heaven and is ultimately defeated by DenLiner Gouka.[3]

The Chameleon Imagin wields a whip and can breathe fire. When Yū Yamagoshi wishes for "a hell of a lot of money," the Chameleon fulfills this wish by robbering banks. When he travels to the past, the Chameleon Imagin begins to destroy various cars while in control of Yamagoshi. The Chameleon Imagin overpowers Den-O Plat Form until Momotaros apologizes for his earlier squabble with Ryotaro and assumes Den-O Sword Form, slicing the Imagin in half at the waist with his Extreme Slash and destroying him.[4]

The Crust Imagin wields a boomerang-like sword and uses seaweed-like tendrils for weapons. When Daiki Saitō wishes to be back on his soccer team, the Crust fulfills this wish by hospitalizing the other members. He then travels to the past and begins attacking the soccer stadium. When destroyed by Den-O Rod Form, the Crust Imagin becomes Gigandeath Hades and is then destroyed by DenLiner Isurugi.[5]

The Crow Imagin wields a cane and uses his feathers as explosive shurikens. When Yumi Saitō wishes to forget about her ex-boyfriend, the Crow Imagin fulfills this wish by destroying anything playing Four Seasons Concerto No. 1: Spring. Once in the past, he "erases" all of the members of Yumi and Toyama's wedding party. The Crow Imagin is defeated by Den-O Sword Form after Rod Form manages to counter his flight ability.[6]

The Rhino Imagin wields a mace and possesses brute strength. When Shinji Kikuchi wishes to be the best karate master in Tokyo, the Rhino fulfills this wish by attacking all of his former competitors. When he travels to the past, the Rhino Imagin destroys the karate arena, and is confronted by Den-O's Sword Form and manages to have the upperhand until Kintaros forms a contract with Ryotaro, turning Den-O to Ax Form. Despite his best attempts, the Rhino's mace is shattered by Den-O's brute strength, allowing him to be struck down by the Dynamic Chop. He then reforms into Gigandeath Hell and is destroyed by DenLiner Rekkou.[7]

The Ivy Imagin wields a double-bladed sword and uses his vines as weapons. After sensing Kensaku's subconscious desire to be with his daughter Kasumi, the Ivy Imagin fulfills this wish by preventing her career from advancing. When he travels to the past, the Ivy Imagin destroys the Kobayashi's hometown, and is eventually defeated by Den-O Ax Form. Due to Kintaros' interference in the past, the Ivy Imagin is prevented from ever making the contract at all, negating his damage.[8]

The Owl Imagin wields a sword and uses his feathers as bombs, just like the Crow Imagin. When Shūji Toyama wishes for the park he works at to become a better place for the stray animals that live in it, the Owl fulfills this wish by first attacking any human who tries to enter the park, then, eventually barricading the entrance to the park with cars, and debris. When he travels to the past, havoc ensues before the Owl Imagin is defeated by Den-O Gun Form, however. The Owl Imagin reform into Gigandeath Heaven and Hades, the Heaven is destroyed by DenLiner Ikazuchi's energy blast and the Hades Gigandeath is destroyed by combined firepower of all time train and Gun Form's Wild Shot.[9]

The slow and less-intelligent Whale Imagin wields a staff with a fluke at one end and has the ability to breathe water from its mouth. When Kōsaku Higuchi wishes to get rid of his drinking problem, the Whale Imagin fulfills this wish by attacking anyone who knew of his drinking problem: former employees and a sake vendor. Once in the past, he attacks people who were having a hanami party under a starlit night sky. The Whale Imagin is confronted by Den-O Sword Form and Gun Form, and is destroyed by Den-O Sword Form.[10]

Another Whale Imagin was amongst the massive army of Imagin that invaded both the past and the present as part of Kai's plan to ensure the Imagins' future, this armed with a sword rather than a staff.

The hot-tempered Wolf Imagin wields a sword able to launch crescent energy beams. When Yuka Sawada wishes to relive her high school days, the Wolf fulfills this wish by vaporizing high school girls and giving their possessions to Yuka. When the Wolf Imagin travels to the past, Gun Form is the first to confront him, stopping the Wolf Imagin from completing its mission. After being stuck for a day in the past with no new information from Kai of Sakurai's location, the Wolf Imagin goes berserk with bored rage and decides to destroy anything in his path to complete the mission. Although both Rod and Ax Form fought the Wolf Imagin, Sword Form is the one that finally destroys him.

The Wolf Imagin later returns in the Kamen Rider Den-O Hyper Battle Video, seen amongst the other Imagin aboard the DenLiner exercising along with them before making his move around Ryutaros' turn. After mocking Ryotaro, he is destroyed by Den-O Liner Form.[11]

The Wolf Imagin is also one of the two antagonistic Imagin featured in the Imagin Anime 2 shorts, making two appearances, as well as in merchandise from Animate.

The Jelly Imagin possesses electrical tentacles and the ability to liquefy his body. When Kōhei Amano wishes to unearth the time capsule that had been left behind by his girlfriend, the Jelly Imagin fulfills its contract by forcing Amano to unearth any time capsule that he sees being buried. Once in the past, the Jelly Imagin attacks a bunch of picnickers that are near the original time capsule's burial site. Though he overpowers Den-O Sword Form, the Jelly Imagin is destroyed by Zeronos Vega Form.[12]

The Tortoice [sic] Imagin is actually two Imagin in one: a dominant and slow tortoise-half with an energetic hare-half generally dormant inside the Imagin's body unless needed. The Tortoice Imagin can fire large pellets out of his mouth and has a serious personality while his hare-half has a playful, childish personality. The wish of the Imagin's contractor, Tanaka, is unclear because the wish is made at the time he is half-awake. However, the Tortoice Imagin is unable to travel back in time because Tanaka cannot remember making a contract. Once Tanaka is able to remember, the Tortoice Imagin travels back in time only to be defeated by Zeronos and Den-O taking on the Imagin and his hare half. However, the two halves reform into Gigandeaths, with Hell attempting to escape until the ZeroLiner corners it. The Heaven is destroyed by DenLiner Isurugi's beams and the Hell Gigandeath is chopped to pieces by Zeroliner Naginata's blades and explodes.[13]

The Scorpion Imagin wield a axe and can fire needle from sting-like hand, he has made a contract to abduct Shiori for Akio, preferring to grant an "easy" wish with no tolerance for those who attempt to meddle in his affairs. Though halted by Den-O twice, the Scorpion managed to go back to time. The Scorpion Imagin was fought by Den-O's Rod Form before Ax Form finishes him off.[14]

The red-eyed Spider Imagin, who wields a sword, made a contract with Masashi for his sister Mayu to see a star, intent on tying her to a radio tower to fulfill it. Though initially defeated by Zeronos, it turned out that the Spider Imagin split itself in two prior to the fight with a more serious version outliving his crazed "brother." The second green-eyed Spider Imagin, able to fires energy web from his arm. Find the way to fulfill the wish without problem by destroying electricity pylon, causing a massive blackout as a result. Once in time, the green-eyes Spider Imagin battled Den-O Gun-Form to avenge his crazed "brother" until future Zeronos interfered and Sword-Form finished the fight.

The red-eyed Spider Imagin later returns in the Kamen Rider Den-O Hyper Battle Video, amongst the other Imagin aboard the DenLiner exercising before making his move around Ryutaros' turn. After mocking Ryotaro, he is destroyed by Den-O Liner Form.[15]

The Bloodsucker Imagin is brought to Shōichi Ike by the Molech Imagin to aid him in keeping Zeronos from interfering in Gaoh's affairs, running off once it did his part. The Imagin then proceeds to get back the stolen jewels that Ike secretly sold, succeeding in fulfilling the contract due to the crisis Ryotaro learned of with Urataros and gang. Though he overpowers Sword Form on two occasions, the Bloodsucker Imagin is no match for the newly accessed Climax Form.[16]

The Molech Imagin is one of Gaoh's subordinates, able to use his tongue as a weapon along with mucus-kicks. He is sent to the year 2007 to set up Gaoh's plan. With the Bloodsucker Imagin's aid, the Molech Imagin found an ideal pawn in Hiroshi Katō, setting up a contract, to help the human acquire a necklace, so he can go back in time with Den-O in pursuit. Though destroyed, the Molech Imagin gives Gaoh and the other Imagin the time they need to hijack the DenLiner.[17]

Kai later created another Molech Imagin as part of his massive army of Imagin that face off against Zeronos Zero Form in the present time as part of Kai's plan to ensure the future of the Imagin.

One of Gaoh's minions, he helped unearthed the GaohLiner by possessing one of the Sanada Ten Braves and having him fire a flaming arrow near the burial site. He also aids his master in fighting the multiple incarnations of Den-O in the Climax Scene. His design is based on the Aztec god Xolotl who transformed himself into an axolotl salamander in order to escape a battle.[18]

One of Gaoh's minions, the Gecko Imagin served his master in fighting the multiple incarnations of Den-O in the Climax Scene.

Kai created another Gecko Imagin, one that teamed with another Newt Imagin in overpowering Den-O Plat Form until Climax Form is accessed. Despite help from the Newt Imagin, he is successfully repelled and subsequently defeated in due part to the teamwork of the Tarōs Imagin.[19]

Another Gecko Imagin is amongst the massive army of Imagin that faces off against Zeronos Zero Form in the present time as part of Kai's plan to ensure the future of the Imagin.

The voice of the Gecko Imagin, Kenichi Suzumura, is also the voice of Ryutaros.

One of Gaoh's minions, the Newt Imagin served his master in fighting the multiple incarnations of Den-O in the Climax Scene.

Kai created another Newt Imagin, one that teamed with another Gecko Imagin in overpowering Den-O Plat Form until Climax Form is accessed. Despite help from the Gecko Imagin, he is successfully repelled and subsequently defeated in due part to the teamwork of the Tarōs Imagin.[20]

The voice of Newt Imagin (Kai's), Kōji Yusa, is also the voice of Urataros.

The Wasp Imagin, able to fire needles from his forehead and wields a rapier, grants Machida's wish to dispose of the evidence of the manslaughter he committed, arriving on the day it occurred. Den-O fought the Imagin in Plat Form, losing until the Taros managed to perfect their teamwork to an extent.[21]

Another Wasp Imagin is amongst the massive army of Imagin that faces off against Zeronos Zero Form in the present time as part of Kai's plan to ensure the future of the Imagin.

The Bluebird Imagin is similar to the Owl Imagin, but can create balls of "fireworks" to throw as weapons. In his first encounter with Sword Form and Deneb, the Bluebird Imagin escapes to fulfill Tōru's wish for his wife to see the fireworks, the Bluebird Imagin fulfill the wish by using his firework on her. He later wounds Deneb while abducting Tōru, with the contract fulfilled. In the past, the Bluebird Imagin is halted by Sword Form, fighting it until he assumes Climax Form.[22]

Another Bluebird Imagin was amongst the massive army of Imagin that invaded both the past and the present as part of Kai's plan to ensure the Imagins' future.

The Rabbit Imagin resembles the hare-half of the Tortoice Imagin, only in a furry white color scheme and wield a sickles. The Rabbit Imagin enjoyed laughing and had his contract holder hanging for his life, granting the man's wish to "fly". Deneb attempted to fight the Rabbit Imagin off with Yuto reluctant to use up his last Zeronos Card. The Rabbit Imagin then fought Ax Form in the past but was greatly outmatched and hid behind a tree in an attempt to escape the deathblow, his final words being that Den-O won't stop the Imagin forever.[23]

The two Anthopper Imagin differ from previous Imagin as they work for the goal to destroy Den-O, picking Fujishiro as an ideal contract holder. The two are ant-like from the left-half of their upper bodies and the right-halves katydid-like. The cold-headed brother, Ari, who wields a shovel-like sword while its maniacal brother, Kirigiris, uses a viola-like sword while taunting his opponent. Ari lures Den-O to a railway for their trap, fighting Gun Form at a disadvantage until Kirigiris makes his move and the two quickly overpower Gun Form. However, Yuto knew that it would be a trap and sent Deneb to interfere. This act forces Ari to use Fujishiro to adbuct Airi, leaving a message for Den-O to fight him and his brother at the Mitsuboshi Factory if he wants Airi back alive. Yuto and Deneb go in Ryotaro's place to save Airi, with Yuto reluctant to transform and use his last card. M-Ryotaro, however, manages to make it before he transforms with payback on his mind. Both Den-O Sword Form and Deneb attempt to fight off the two Anthopper brothers until Yuto arrives again and transforms into Zeronos for the last time. Zeronos finishes off Ari after a long battle while Den-O assumes Climax Form and finishes off Kirigiris as payback for beating up Ryutaros.

Ari later returns in the Kamen Rider Den-O Hyper Battle Video, hiding among the participating Imagin exercising along with them until he makes his move around Ryutaros' turn. After mocking Ryotaro as he and the evil Imagin engage him, he is destroyed by Den-O Liner Form.[24]

Wielding a pistol, the Kraken Imagin is able to use it as well as his tentacles for weapons. The Kraken Imagins fulfill his contract with a man for a piano. But, much to its dismay, his contract wasn't fully completed. The Kraken Imagin battled Den-O Sword Form, but the fight ended in a draw. The Kraken later succeeded in going back through time, where he fought Den-O Rod Form and was defeated by him. However, the Kraken Imagin turning into a massive flock of Heavens and a pack of Hells that destroy the entire district, negating the existence of those there, only power of all DenLiners destroys the several Heavens and Hells, restoring everything within time and memory to normal, except for the original contract holder.[25]

The Mole Imagin is another Imagin out to kill Den-O, able to spin and burrow. As well as able to fires energy laser. The serious "Ax-Hand" Mole Imagin completes Yamaguchi's contract, arriving to the day that he lost a singing contest. Den-O Ax Form arrives to fight him, only to deal with both him and his two brothers clones: the crazed Claw-Hand and the effeminate Drill-Hand. The Mole Imagin trio proves too much for Ax Form as he suddenly begins losing his sync with Ryotaro. The two clones depart while their big brother remained to finish the job. Yuto arrives and accepts the elder Sakurai's gift and becomes Zeronos again, defeating the Ax-Hand Mole Imagin as he was about to retreat. The brothers later destroying city apart to lure Den-O and Zeronos back in time to avenge their older brother. Sword Form and Zeronos battle the two Imagin until Momotaros loses his sync and Den-O is reverted to Plat Form. Both Claw-Hand and Drill-Hand are nearly successful in defeating Plat Form and Zeronos Vega Form until the Tarōs arrive and give Ryotaro the power to assume Liner Form. The Mole Imagin are no match for Liner Form as Ryotaro defeats them with his newfound power.[26]

Among the bulk of the massive Imagin army Kai creates for the purpose of killing Airi are the New Mole Imagin (NEWモールイマジン,Nyū Mōru Imajin?). These Imagin spots black vests, as opposed to the red vests the regular Mole Imagin wear, and are armed with numerous other weapons for hands.

The Leo Imagin is Kai's subordinate and uses his three Leo Soldiers (レオソルジャー,Reo Sorujā?) to kill Momotaros, Urataros, and Kintaros in the Time Station while he handles the task of killing R-Ryotaro upon fulfilling his part in Kai's plan. But Yuto drives the Imagin away with his attack and Momotaros, Urataros, and Kintaros use their versions of Den-O's finishers to destroy his Leo Soldiers. When Den-O Sword Form appears, the Leo Imagin travels back in time through Kai with Den-O in pursuit. But before the fight could start, Momotaros loses his sync with Den-O, leaving Ryotaro to assume Liner Form and fight the Leo Imagin, using the DenKamen Sword's RyuGun Mode to destroy him.[27]

The Panda Rabbit Imagin, a light-weight version of the Rabbit Imagin with a sword, finished his contract of getting its contract holder to the company he wanted to work at, nearly killing him in the process. He was about to go back into time, but got cut off by M-Ryotaro, who decided to use the weakling for Ryotaro to study his fighting moves as Kai looked on from afar. Though Sword Form succeeds in destroying the Imagin, Ryotaro travels back to time to understand the reason why the evil Imagin desire to go back to the past.[28]

The two Snail Imagin serve Kai. Under Kai's orders, the female Snail Imagin, a female sadistic Imagin who wield a whip and babies her opponents, uses the teacher of Yuto Sakurai to go back into Yuto's past and take out the Yuto of that time, thus negating Yuto from the present timeline. Ryotaro refuses to accept this loss and assumes Liner Form to battle the female Snail Imagin, weakening her with the DenKamen Sword's other modes before finishing her off with MomoSword mode. In spite of her death, she succeeds in ridding her master of Sakurai by eliminating Yuto as it seemed.

The male Snail Imagin, who armed with a pistol, is later sent by Kai to abduct Hana to force Ryotaro to consider Kai's offer to aid him in ensuring an ideal future. But when Ryotaro refuses, the Snail Imagin attempts to kill him when Yuto manages to return to existence, forcing Kai to send the male Snail Imagin back into time to kill Sakurai. But this time, the male Snail Imagin are no match for Zeronos newly accessed Zero Form as Yuto using the red Zeronos card.

Another male Snail Imagin was amongst the massive army of Imagin that invaded both the past and the present as part of Kai's plan to ensure the Imagins' future.[29]

A red-colored version of the Kraken Imagin with suction-cup trimmings on its body, the Oct Imagin uses ink smoke bomb to temporarily blind the opponent and uses tentacle to control or inanimate object, controlling and sabotage Denbird and a truck against Den-O. He intends to grant Shōko's wish by getting Yuto, even though the Imagin has to bring him alive for the contract to be completed. But when the Oct Imagin travel back in time, he can now kill Yuto without any penalty, by control over the ZeroGasher against Zeronos. Although destroyed by the combined effort of Liner Form and Zero Form, a piece of his tentacle enter the AuraLiner, causing the time railway to rampage and turning into hydra-like monster that KingLiner destroys them.[30]

The pain-mongering Armadillo Imagin carrying a ball and chain as his weapon and able to roll up into a ball, as well as able to burrow underneath, much like the Mole Imagin. the Imagin completes his contract to "cut" Ōzaki and goes back into the time when Ōzaki was recruited by the Shirakaku. The Armdillo Imagin overpowers both Zeronos Zero Form and Den-O Liner Form until the DenLiner provides the two with an escape from the losing fight. However, the Imagin manages to stow onto the DenLiner and arrives at the Time Station, seeing it much fun to smash the station. But Urataros and Kintaros hold him off with Ryutaros supporting them until both Momotaros and Ryotaro arrive. Each of the Tarōs fight the Imagin in their respective Den-O forms before assume into Climax Form to finish him off, their teamwork overpowering his strength.[31]

The Albinoleo Imagin is Kai's subordinate, a stronger white version of the Leo Imagin. Sent to kill Airi, he easily overpowers Den-O Liner Form and Zeronos Zero Form until elder Sakurai arrives, turning the tables. After being pummeled by the trio of Riders, the Altair Form and Zeros Form leave the Albinoleo Imagin open for Liner Form's DenKamen Slash, which destroys him.[32]

Using a cane as his weapon, the Snowman Imagin fulfills his contract with the Storekeeper, emptying out his stock by giving them to everyone as presents. Den-O Sword Form fails to stop the Imagin from going back in time to find the Ryotaro of that time. But Liner Form is able to destroy the Snowman Imagin when he attempts to outrun the final blow.[33]

The Death Imagin is the leading force of Kai's Imagin army, created by using all Kai's remaining memories, it is serves as an integral part of Kai itself. And if the Death Imagin were destroyed, Kai and his Imagin army would dissolve into sand. The Death Imagin wields a scythe with double blades at both ends, though he overpower both Den-O Liner Form and Zeronos Zero Form, the Death Imagin is eventually destroyed by Den-O Sword Form and the combined energies of all the good Imagin, causing Kai and Imagin army to dissolve into nothing as a result of destruction of Death Imagin.[34]

The Ghost Imagin is one of Shiro's Imagin followers and possesses Ryotaro, having him assume Kamen Rider Yuuki's Skull Form. While possessing Ryotaro, Ryotaro is referred to as "A-Ryotaro" (A良太郎,Anazā Ryōtarō?), with the A standing for "Another".

The Piggies Imagin has two faces on his shoulder pads, each of which has his own separate personality from the actual head and are referred to as his younger brothers. When Hiroshi Kikuchi makes a contract so he can prove himself to be a hero to Airi Nogami, the Piggies Imagin orchestrates the hijacking of the DenLiner to get Den-O out of the way. However, Yuto's interference forces the Imagin to change plans to complete his contract with Kikuchi. However, once the Piggies Imagin feels the contract is complete, Kikuchi refuses to accept it as he was not able to play the part of the hero, making the Piggies Imagin unable to travel back in time. After being knocked away by Zeronos, the Piggies Imagin faces Den-O before he assumes Climax Form and is cut into many pieces.

The Mantis Imagin is a female masochist Imagin with the ability to spray a poisonous purple gas and wield twin rapiers as her weapons. Her goal is to allow a Miku Uehara from the near future to see her grandmother for the last time, as in her timeline she kept putting off celebrating her birthday with her grandmother up until her grandmother died before it could happen. Before the Mantis Imagin can complete her contract and go back in time, New Den-O defeats her.

Whenever an Imagin is defeated, they sometimes reform their bodies along with a berserk state of mind, warping into one of three types of massive creatures called Gigandeath (ギガンデス,Gigandesu?, from "Gigantes"). The number of Gigandeaths emerging from an Imagin can be from a single Gigandeath, to two different types, to an entire army of them. These monsters are mindless and are filled by the urge of destroy. Whenever a Gigandeath emerges, only a Time Train can take it out. All three Gigandeaths are augmented into the Nega DenLiner's arsenal.